Electrosurgery is the process of using the direct application of electric currents to cut and/or desiccate tissue and stop blood flow. It has been in use for a number of years, but it is constantly being perfected and revolutionized.
Electrosurgery is utilized for all different types of procedures in the medical industry today. Some of these include dermatological, cardiac, vascular, orthopedic, and dental surgeries. It is especially useful in situations and in areas of the body where cutting can induce a great deal of blood loss.
Because it has the power to coagulate the vessels around an incision, it can minimize blood loss. Since the introduction of electrosurgery in the 1920's many surgeries have been enabled because electrosurgical tools can control bleeding while the use of a scalpel cannot control bleeding.
In principle, it can be differentiated between the monopolar electrosurgery and the bipolar electrosurgery.
In the monopolar electrosurgery a single electrode or pencil/instrument is used for carrying the electrical current to the surgical or incision site. This current travels through the body of the patient to the patient who is grounded. Higher voltages are used for coagulation while lower voltages are used for cutting. However in the bipolar electrosurgery the patient's body is not used as a conductor to carry current and for this reason this technique is most appropriate where the spread of thermal damage to adjacent tissues creates the potential for patient harm. Excessive thermal spread could, for example, damage an adjacent nerve to the body's region being operated.
By applying bipolar electrosurgery techniques, usually, current is delivered through one tip of a bipolar instrument and is returned back to the generator through the opposing, tip of the instrument.
Nowadays, many modern medical devices use integrated electrical circuitry, and it is important that they are properly insulated. The risk of injury from electrical shock to the surgeon and the patient can be extremely high if the metal components are not properly insulated.
The patent document WO 93/20747 discloses a guide wire for supporting monopolar arcing for cutting tissue and for ablating occlusions which includes a flexible metal wire (which is a corrosion-resistant metal or alloy, such as stainless steel) including a distal end, an electrically insulating coating which is extended along the wire, and an electrically and thermally insulating tip having a distal end and which is attached to the wire, and the wire is extended through the electrically and thermally insulating tip and forms an electrode at the distal ends of the wire and the tip. The insulating coating must be according to WO 93/20747 a medically compatible electrical insulator, such as polyurethane, polyimide, polyethylene, and preferably tetrafluoroethylene (TEFLON) because of its very good sliding properties. Furthermore, the insulating coating must be sufficiently thick to protect a surgeon using the guide wire and the patient from electrical shock and at the same time sufficiently thin so that the insulated wire fits into small lumens.
The patent document EP1905370 discloses an electrosurgical instrument and, more particularly, coatings for an electrosurgical instrument which uses thermogenic energy for cauterization, coagulation and tissue joining/welding in combination with staples to form a hemostatic staple/coagulation/cut line tissue. In accordance with EP1905370 the electrosurgical instrument has an end effector which can have a first pole electrode and a second pole electrode and a staple cartridge having at least one staple therein, depending on the type of energy received by the end effector. However, in all cases the electrosurgical instrument comprises a non-conducting or dielectric coating which can be placed depending on the type of construction of the instrument:                on at least a part of the second pole electrode, or        on at least one of the first and second pole electrodes where the dielectric coating can prevent direct tissue contact with at least one of the electrically active electrodes, or        on at least one staple of the staple cartridge for reducing formation of a surface charge thereon during application of bipolar energy to tissue.        
The non-conducting or dielectric coating according to EP1905370 could be but is not limited to a polytetrafluoroethylene (PTFE), titanium dioxide, or polymers based on paraxylene, or an epoxy.
Furthermore, it is known from the state of the art, that today some electrosurgical instruments, such as bipolar electrical surgical scissors, are being coated with Al2O3 coatings deposited by thermal spray techniques. However, this practice can be complex and is very expensive.
The objective of the present invention is to provide a coating system and method for producing insulating coatings which preferably exhibit simultaneously good wear resistance and/or good sliding properties. Furthermore, it is an objective of the present invention to provide an advantageous method for producing the coating systems according to the present invention which allows coating parts of electrosurgical devices which can have different forms and dimensions in an uncomplicated and not expensive way.